As soon as Richard Grant, executive
director of the Diebenkorn Foundation, glimpsed the three drawings in an Upper
East Side apartment several years ago, he knew there was a problem.

The artwork on the wall had been
previously identified by the artist’s estate as fake Richard Diebenkorns. But
here they were again, proudly displayed as Diebenkorns by a new owner who had
no idea he had bought discredited drawings.

For organizations like Mr. Grant’s
that are charged with protecting an artist’s legacy, the job of patrolling for
fakes has become something like a game of Whac-A-Mole.

“You put it down, and then five, seven
years later, poof!, and there it is again,” he said by phone from the
foundation’s offices in California.

The resale of fakes is a persistent
and growing problem without a good solution, say collectors, dealers, artist
estates and law enforcement agencies. Although the Federal Bureau of
Investigation can seize forgeries in criminal cases, these represent only a
tiny portion of the counterfeit art that is circulating.

“They churn through the market,” James
Wynne, an F.B.I. special agent who handles art forgery cases, said of fakes.

There are no clear rules for what
happens to phony art after it is identified. “It all depends what the facts
are, what the art is, how many works are involved and how expensive they are,”
he said.

Art whose authenticity is disputed
occupies a special sort of limbo, as demonstrated by the settlement last month
between Knoedler & Company, a Manhattan gallery that abruptly closed last
year, and a customer who accused that gallery of selling him a forged Jackson
Pollock for $17 million.

The F.B.I. is investigating whether
that painting, known as “Silver Pollock,” might be part of a larger cache of
forgeries. But no charges have been brought and the gallery maintains that the
work is authentic. So what happens to a $17 million painting that some people
consider a fake?

Given the publicity surrounding this
particular case, a sale any time soon would be surprising, art lawyers and
dealers agree. But nothing in criminal law would necessarily prevent the owner
from selling it today as a Pollock. (Details of the settlement are
confidential, including who owns the artwork now.)

When it comes to undisputed fakes, law
enforcement officials try to halt resales by such practices as stamping works
as fake or, in rare cases, destroying them. Each option has drawbacks, including
the possibility of mistakenly destroying an authentic work.

Ultimately, though, both the police
and buyers mostly rely on the art market to police itself.

Artist foundations and estates that
find fakes on eBay or at small auction houses can inform the dealer or Web
site, but they have no authority to seize or mark the work. Frequently, they
say, counterfeits go underground only to re-emerge later, labeled as the real
thing.

Jack Cowart, executive director of the
Lichtenstein Foundation, said that during the years that it authenticated works
by Roy Lichtenstein, he regularly noticed that collectors informed that they
had a fake would later quietly sell it as genuine. “And then we’d find somebody
else would send the same work to us six months later” asking for it to be
authenticated, he said.

In France, Switzerland and other
countries that recognize the “moral rights” of an artist, heirs or foundations
like Lichtenstein’s can ask the courts for permission to destroy a fake. But
Ronald D. Spencer, a Manhattan lawyer and editor of the art-law handbook “The
Expert Versus the Object: Judging Fakes and False Attributions in the Visual
Arts,” said he was glad that is not done in the United States. The notion is
“an anathema,” he said, noting how frequently opinions about authenticity can
change. Just two months ago, for example, three J. M. W. Turner paintings that
had been dismissed as fakes were reclassified as genuine.

“Stamp it, by all means, so that any
subsequent owner knows that it was considered a fake, but don’t destroy works,”
Mr. Spencer said, echoing the view of many art dealers. If destruction becomes
routine, he added, a genuine work will mistakenly be consigned to the shredder
at some point.

Marking a work was the course taken in
2011 by the Dedalus Foundation, a nonprofit created by the artist Robert
Motherwell, after it identified a putative Motherwell painting as forged.

As part of a civil settlement, Dedalus
demanded that the work be permanently marked as a fake. Now on the back of the
work, “Spanish Elegy,” an indelible stamp states that “this painting is not an
authentic work by Robert Motherwell but a forgery.”

The effort to keep fakes off the
market may be most hampered by the reluctance of those in the know to speak
out. Art experts and institutions, most prominently the Andy Warhol Foundation
and the Lichtenstein Foundation, have stopped authenticating artwork, or
pointing out suspected fakes, for fear of being dragged into a lawsuit by the
owner of a work they rejected.

I very much appreciate my articles and
photos appearing on fellow bloggers' sites, popular broadsheets, and local
broadcast news segments, but I would appreciate even more a request for
permission first.